(1) Field of the Invention
The present invention relates to tubular linear synchronous motor (TLSM) door assembly for providing motive force to a door or doors. More specifically, this invention relates to an apparatus incorporating a TLSM with control circuitry to provide sensor-less control of an elevator door configuration.
(2) Description of Related Art
Use of motor assemblages and associated control mechanisms for accomplishing the automated opening and closing of doors is well known. Such assemblages are often found in the context of elevators wherein their arrangement gives rise to concerns regarding efficiency, noise, lifetime, and maintenance of the assemblage.
Common door control implementations require a sensing apparatus, such as an optical sensor, for determining the precise location of a door or doors at all times. While optical sensors can be used to determine the position of a door to within fractions of a millimeter, traditional elevator door implementations require an accuracy only on the order of a millimeter or so.
What is needed therefore is a mechanism for operating doors, particularly elevator doors, in a non-contact manner. By non-contact, it is meant that operation of the motor does not result in the physical contact by, movement of, and resulting friction between moving parts. It would likewise be advantageous for such a system to provide continuous monitoring of the position of the door or doors without the need for expensive and maintenance intensive sensors.